Well, Polis Massa is a great place for your anti-tank. Well, that is next to a nicely tweaked genonsis as CIS with AI population of 5 on each side(aim for the usually unmanned ATTE).

Be CIS and go outside for tank hunting. You can walk up to the week point point blank and fire w/o worry since there will be no enemy troopers.

While you are at it get your pistol awards also before killing yourself. Stand right outside the forcefield of the enemy base, aim, dart in and fire, dart out at once. You can never get hurt like that.

After you get the award you can hop on a tank and drive into the middle garage, now pound your firepower down the hallway and get war hero.